Don't display WordPress admin notices on the setup wizard screen

### Reproduction steps

+ Install LifterLMS on a fresh WordPress site (ideally with the twenty twenty theme)
+ After activation, you'll be redirected to the setup wizard
+ Observe the admin notices "flash" and then disappear as the wizard loads -- this doesn't always happen, it depends on the order of asset loading and the internet connection speed. I find it happens pretty regularly on myliftersite.com sites but not on my local.

### Solution

It would be preferable to *remove* the admin notices action from the wizard screen so that notices aren't output at all.